The proper handling of webs is of importance in many industries, particularly in the printing industry. Today's high speed printing presses print on web drawn from a roll mounted on the roll support arms of a roll stand located upstream from the printing press. In order to avoid having to shut down the press each time a web roll expires, a splicing mechanism is invariably incorporated into the roll stand to enable the trailing end of the expiring web to be spliced to the leading end of the web on a fresh or full-sized web roll. Also, a web accumulator or festoon is typically located between the splicer and the press so that the web being drawn from the expiring roll can be slowed down or stopped during the splicing operation, with the printing press drawing its web requirements from the accumulator at line speed so that there is no interruption or delay in printing. After the splicing operation is completed, the accumulator is replenished with web drawn from the new roll so that there will be enough web available in the accumulator to supply the needs of the printing press when the next splicing operation occurs upon expiration of the new web roll.
As printing speeds become higher and higher, it is obvious that more and more paper is required to meet the needs of the press. These demands can be met by making the web rolls larger or by changing the rolls more frequently. Actually, some of today's high speed presses consume paper and other webs so fast, e.g. in excess of 2000 ft. per minute, that both of these solutions are required to be used. The rolls serving such presses can be as large as 8 ft. in diameter and weigh as much as 6,000 lbs. or more. It is obvious, then, that the efficient handling of these large and heavy web rolls is a prerequisite to an efficient printing operation.
In practice, however, improvements in the handling of web rolls have not kept pace with the operational advances in presses and other web-consuming machines. Indeed, it is difficult to automate the handling of such rolls because the rolls have variable tapers, eccentricities, weight imbalances and other irregularities which make it difficult to precisely control the positions of the rolls for proper loading into the splicers. Resultantly, web rolls are still hoisted onto small trucks and hauled to the web splicers where they are hoisted into place on the roll support arms of the splicers. Also, the leading edges of the webs are prepared for the next splicing operation right at the splicers. Typically, this is a fairly time-consuming procedure involving squaring off the web leading edge, applying double-faced adhesive tape to that edge, and taping the edge to the outside of the roll or to a preparation bar in the splicer. Bearing in mind that a large printing operation may have many presses running simultaneously, each with its own upstream splicer, it is apparent that large amounts of manpower and equipment are required just to service the splicers to keep the presses supplied with paper to print on.
Also, the splicers themselves have not kept pace with today's presses and other high-speed web consuming machines. Some of them require that a roll be mounted to the roll support arms of the splicer by way of a roll shaft. The requirement for the shaft complicates the loading of the web roll on the splicer. Also, those shafts able to support the heavier and wider web rolls in use today, are often not perfectly concentric. Resultantly, at high press speeds, even a small shaft eccentricity or irregularity can cause tension upsets in the web which can result in tearing and breaking of the web, necessitating a complete shutdown of the downstream press or other web-consuming machine.
Other contemporary splicers have arms which support the web roll by way of chucks which project into the opposite ends of the roll core. These have the advantage of easy loading and they do not require a shaft extending through the roll. However, they usually splice the web on the fly. For many webs, particularly the wider ones, better and more reliable splices are made when the webs being spliced are stationary at the time of splicing.
Accordingly, it would be highly desirable if there were available a system for handling web rolls so that the rolls supplying all of the splicers in a given facility could all be prepared for splicing at a single roll preparation area and be transported from that area automatically to those splicers of that facility then in need of more paper or web and be loaded automatically into the respective splicers with their web leading edges in position for splicing with splicing taking place automatically to satisfy the web requirements of the presses or other web-consuming machines served by those splicers.
Accordingly, the present invention aims to provide an automatic web roll handling system for servicing splicers, especially those which splice at zero speed.
Another object of the invention is to provide a system for transporting large and heavy web rolls automatically from a single roll preparation area to selected splicers in a group of splicers on a demand basis.
Another object is to provide such a system which permits all roll preparation to be performed at a single preparation area remote from the splicers with the rolls then being transported automatically to the splicers on a demand basis and loaded onto the respective splicers and the webs on the rolls then being spliced to the running webs in those splicers all without any human intervention or control.
A further object of the invention is to provide an improved guided vehicle for transporting a large and heavy web roll between a roll preparation area and a splicer.
A further object of the invention is to provide such a vehicle which automatically positions its supported web roll with respect to the roll support arms of the destination splicer.
Still another object of the invention is to provide a guided transport vehicle of this type which is safe to use in a personnel work area.
A further object of the invention is to provide a turret splicer for use with a guided roll transport vehicle which can splice the web drawn from a roll taken from the vehicle at zero speed.
Other objects will in part be obvious and will in part appear hereinafter. The invention accordingly comprises the features of construction, combination of elements, and arrangement of parts which will be exemplified in the following detailed description, and the scope of the invention will be indicated in the claims.